CodeQL Security Scan
trailofbits/skills
Scans a codebase for vulnerabilities with CodeQL's data flow and taint tracking in run-all or important-only modes, including data extensions for project-specific sources and sinks.
REST API security hardening with authentication, rate limiting, input validation, security headers.
Install API Security Hardening
$ npx skills add secondsky/claude-skills --skill api-security-hardening -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install secondsky/claude-skills api-security-hardening --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/api-security-hardening/skills/api-security-hardening .claude/skills/api-security-hardening && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "api-security-hardening" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/api-security-hardening/skills/api-security-hardening into .claude/skills/api-security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-security-hardening", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/secondsky/claude-skills/tree/main/plugins/api-security-hardening/skills/api-security-hardeningType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add secondsky/claude-skills --skill api-security-hardening -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install secondsky/claude-skills api-security-hardening --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/plugins/api-security-hardening/skills/api-security-hardening .agents/skills/api-security-hardening && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "api-security-hardening" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/api-security-hardening/skills/api-security-hardening into .agents/skills/api-security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-security-hardening", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add secondsky/claude-skills --skill api-security-hardening -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install secondsky/claude-skills api-security-hardening --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/plugins/api-security-hardening/skills/api-security-hardening .cursor/skills/api-security-hardening && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "api-security-hardening" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/api-security-hardening/skills/api-security-hardening into .cursor/skills/api-security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-security-hardening", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/secondsky/claude-skills.git --path plugins/api-security-hardening/skills/api-security-hardening--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add secondsky/claude-skills --skill api-security-hardening -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install secondsky/claude-skills api-security-hardening --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/plugins/api-security-hardening/skills/api-security-hardening .gemini/skills/api-security-hardening && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "api-security-hardening" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/api-security-hardening/skills/api-security-hardening into .gemini/skills/api-security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-security-hardening", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install secondsky/claude-skills api-security-hardeningInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add secondsky/claude-skills --skill api-security-hardening -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/plugins/api-security-hardening/skills/api-security-hardening .github/skills/api-security-hardening && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "api-security-hardening" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/api-security-hardening/skills/api-security-hardening into .github/skills/api-security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-security-hardening", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add secondsky/claude-skills --skill api-security-hardening -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install secondsky/claude-skills api-security-hardening --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/plugins/api-security-hardening/skills/api-security-hardening .opencode/skills/api-security-hardening && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "api-security-hardening" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/api-security-hardening/skills/api-security-hardening into .opencode/skills/api-security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-security-hardening", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
api-security-hardening- GitHub stars
- 227
- Token cost
- ~718 tokens
- SKILL.md length
- 107 words
- Files
- 2 (incl. references)
- Skills in repo
- 168
- Repo updated
- First seen
- Licence
- MIT
At a glance
REST API security hardening with authentication, rate limiting, input validation, security headers.
- Production APIs
- SKILL.md covers Security Middleware Stack…, Input Validation, Security Headers and Security Checklist, plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Security audits
What it does
API Security Hardening is an agent skill from secondsky/claude-skills. REST API security hardening with authentication, rate limiting, input validation, security headers. Use for production APIs, security audits, defense-in-depth, or encountering vulnerabilities, injection attacks, CORS issues.
Its SKILL.md is about 720 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/python-nginx.md`).
It sits in Security, covering Security review and Secure coding. It works with NGINX and Python. The repository describes itself as: Production-ready skills for Claude Code CLI - Cloudflare, React, Tailwind v4, and AI integrations. The licence is MIT.
When your agent uses it
- Production APIs
- Security audits
- Defense-in-depth
- Encountering vulnerabilities
Example prompts
- “/api-security-hardening”
Requirements
- Python 3
What it can do on your machine
Read from SKILL.md and the folder at commit 8837836. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are javascript).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
API Security Hardening loads about 718 tokens when it runs, and up to ~1.8k if it reads all its reference files. Until then it costs about 62 tokens; SKILL.md has 107 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from secondsky/claude-skills at commit 8837836, republished under its MIT licence (© secondsky). 107 words, ~718 tokens.
Download SKILL.mdSave it as
.claude/skills/api-security-hardening/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.- name
- api-security-hardening
- description
- REST API security hardening with authentication, rate limiting, input validation, security headers. Use for production APIs, security audits, defense-in-depth, or encountering vulnerabilities, injection attacks, CORS issues.
- license
- MIT
API Security Hardening
Protect REST APIs against common vulnerabilities with multiple security layers.
Security Middleware Stack (Express)
const helmet = require('helmet');
const rateLimit = require('express-rate-limit');
const mongoSanitize = require('express-mongo-sanitize');
app.use(helmet());
app.use(mongoSanitize());
// For input sanitization, see the `xss-prevention` skill — do NOT use the
// deprecated `xss-clean` package (unmaintained since 2018; its own README
// recommends migrating off it).
app.use('/api/', rateLimit({
windowMs: 15 * 60 * 1000,
max: 100
}));
app.use('/api/auth/', rateLimit({
windowMs: 15 * 60 * 1000,
max: 5
}));Input Validation
const { body, validationResult } = require('express-validator');
const escapeHtml = require('escape-html');
app.post('/users',
body('email').isEmail().normalizeEmail(),
body('password').isLength({ min: 8 }).matches(/[A-Z]/).matches(/[0-9]/),
// express-validator v7+ removed the built-in .escape() sanitizer; use a
// customSanitizer backed by `escape-html` to HTML-escape the value.
body('name').trim().isLength({ max: 100 }).customSanitizer(v => escapeHtml(v)),
(req, res) => {
const errors = validationResult(req);
if (!errors.isEmpty()) {
return res.status(400).json({ errors: errors.array() });
}
// Process request
}
);Security Headers
app.use((req, res, next) => {
res.setHeader('Content-Security-Policy', "default-src 'self'");
res.setHeader('X-Frame-Options', 'DENY');
res.setHeader('X-Content-Type-Options', 'nosniff');
res.setHeader('Strict-Transport-Security', 'max-age=31536000; includeSubDomains');
res.setHeader('X-XSS-Protection', '1; mode=block');
next();
});Security Checklist
- HTTPS everywhere
- Authentication on all protected routes
- Input validation and sanitization
- Rate limiting enabled
- Security headers configured
- CORS restricted to allowed origins
- No stack traces in production errors
- Audit logging enabled
- Dependencies regularly updated
Additional Implementations
See references/python-nginx.md for:
- Python FastAPI security middleware
- Pydantic input validation with password rules
- Nginx SSL/TLS and security headers configuration
- HTTP Parameter Pollution prevention
Never Do
- Trust user input without validation
- Return detailed errors in production
- Store secrets in code
- Use GET for state-changing operations
- Disable security for convenience
© secondsky, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 1 other file (references) in plugins/api-security-hardening/skills/api-security-hardening of secondsky/claude-skills.
- SKILL.md
- references/python-nginx.md
Open the folder on GitHubat commit 8837836
Compare with similar skills
API Security Hardening next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| API Security Hardening this skillsecondsky/claude-skills | 227 | — | ~718 | Automated safety check: Pass | MIT | |
| CodeQL Security Scantrailofbits/skills | 7.4k | — | ~4.6k | Automated safety check: Notes | CC-BY-SA-4.0 | |
| Security AuditTheDecipherist/claude-code-mastery | 550 | — | ~1.3k | Automated safety check: Notes | MIT | |
| Python kwargs setattr Allowlistmicrosoft/onnxruntime | 22k | — | ~737 | Automated safety check: Pass | MIT | |
| Cb Security HardeningBlkLeg/CircuitBreaker | 201 | — | ~2.1k | Automated safety check: Pass | MIT | |
| Agent-Core Security ChecklistopenJiuwen-ai/agent-core | 446 | — | ~1.7k | Automated safety check: Notes | Apache-2.0 |
Similar skills
- Official
Security Audit
TheDecipherist/claude-code-mastery
Checks a codebase for hardcoded secrets, vulnerable dependencies, weak input handling, weak authentication and unsafe transport settings before deployment or merge.
- Official
Python kwargs setattr Allowlist
microsoft/onnxruntime
Shows how to replace unsafe hasattr and setattr loops over user-controlled kwargs with an explicit allowlist when configuring ONNX Runtime option objects.
Cb Security Hardening
BlkLeg/CircuitBreaker
Enforces Circuit Breaker security hardening conventions across backend, frontend, Docker, and nginx.
Agent-Core Security Checklist
openJiuwen-ai/agent-core
A ten-category security checklist for the agent-core codebase, to run before any security-sensitive change or pull request: secrets, input validation, SQL, access control and prompt injection.
Security Review Checklist
ZeroDeng01/sublinkPro
Checklist-driven security review for changes to authentication, authorization, MFA, secrets, input validation and other security-critical code.
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Categories
Questions about API Security Hardening
What does API Security Hardening do?
REST API security hardening with authentication, rate limiting, input validation, security headers. API Security Hardening is an agent skill from secondsky/claude-skills. REST API security hardening with authentication, rate limiting, input validation, security headers.
When should I use API Security Hardening?
API Security Hardening fits situations like: production APIs; security audits; defense-in-depth; encountering vulnerabilities.
How do I install API Security Hardening in Claude Code?
Run `npx skills add secondsky/claude-skills --skill api-security-hardening -a claude-code`. Or copy the skill folder (plugins/api-security-hardening/skills/api-security-hardening in secondsky/claude-skills) into .claude/skills/api-security-hardening in your project. Claude Code loads it when a task matches its description.
How do I install API Security Hardening in Codex?
Run `npx skills add secondsky/claude-skills --skill api-security-hardening -a codex`. Or copy the skill folder (plugins/api-security-hardening/skills/api-security-hardening in secondsky/claude-skills) into .agents/skills/api-security-hardening in your project. Codex loads it when a task matches its description.
Can I use API Security Hardening in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add secondsky/claude-skills --skill api-security-hardening -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/api-security-hardening, .gemini/skills/api-security-hardening, .github/skills/api-security-hardening and .opencode/skills/api-security-hardening in your project.
What does API Security Hardening need to run?
SKILL.md names no scripts, command-line tools or credentials: API Security Hardening is instructions for the agent only. Our summary lists: Python 3.
Does API Security Hardening access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is API Security Hardening safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does API Security Hardening use?
API Security Hardening is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does API Security Hardening use?
About 718 tokens (SKILL.md is roughly 2.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1k tokens, read only when the agent opens those files.
What are the alternatives to API Security Hardening?
Skills that share tags, products or a category with API Security Hardening: CodeQL Security Scan (trailofbits/skills, 7.4k stars), Security Audit (TheDecipherist/claude-code-mastery, 550 stars), Python kwargs setattr Allowlist (microsoft/onnxruntime, 22k stars) and Cb Security Hardening (BlkLeg/CircuitBreaker, 201 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains API Security Hardening?
secondsky (a GitHub user) maintains it in secondsky/claude-skills, which has 227 GitHub stars. The repository holds 168 skills in this directory. The repository was last updated on September 28, 2026.
Source: secondsky/claude-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.